Serum 5-S-cysteinyldopa levels in patients with psoriasis undergoing narrowband ultraviolet B phototherapy.
BACKGROUND
Ultraviolet (UV) B radiation from sunlight can result in tanning or burning of the skin. Narrowband UVB (NB-UVB), a relatively new light source that is not yet widely available, is effective for treating generalized psoriasis without the use of psoralens.


OBJECTIVE
The melanin-related metabolite 5-S-cysteinyldopa (5-S-CD), which reflects pheomelanin production, has been used as a biological marker of melanoma progression, but there are no studies available on therapeutic UVB effects on serum 5-S-CD of human subjects. In the present study, we measured the time course of changes in serum levels of 5-S-CD in patients with psoriasis undergoing NB-UVB phototherapy.


METHODS
In total, 11 Japanese patients with generalized psoriasis vulgaris received NB-UVB treatment five times per week, at an initial dose of 0.1 J/cm(2). The dose was increased by 10-20% per treatment for > 20 treatments. Serum samples were taken before and 3, 7, 10, 14 and 28 days after phototherapy.


RESULTS
After 4 weeks of NB-UVB treatment, 9 of 11 patients were in remission, confirming the effectiveness of NB-UVB for treating Japanese patients with psoriasis. Two patients withdrew before day 28 because of other complications. Mean level of 5-S-CD in serum was significantly increased on day 7, 10 14 and 28 compared with the level before phototherapy and it peaked on day 10.


CONCLUSIONS
Serum 5-S-CD levels were significantly increased by therapeutic UVB exposure. Sustained levels of 5-S-CD in serum appear to reflect the degree of skin injury during NB-UVB phototherapy.
Kikuchi
K
K
Department of Dermatology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan. kikuchi-der@h.u-tokyo.ac.jp
Wakamatsu
K
K
Tada
Y
Y
Komine
M
M
Ito
S
S
Tamaki
K
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D003548:Cysteinyldopa / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011565:Psoriasis / Q000097:blood* / Q000532:radiotherapy; D012867:Skin / Q000528:radiation effects; D018709:Statistics, Nonparametric; D013995:Time; D016896:Treatment Outcome; D014467:Ultraviolet Therapy / Q000009:adverse effects*
D015415:Biomarkers; D003548:Cysteinyldopa